At least some of the exemplary embodiments described herein relate to methods of using ampholyte polymeric compounds as gelling agents in subterranean operations, and treatment fluid compositions relating thereto.
Viscosified treatment fluids are used in many subterranean operations. For example, in fracturing and gravel packing operations, viscosified treatment fluids may be used to suspend and transport particulates to a desired location in a wellbore penetrating the subterranean formation and/or the subterranean formation, so as to form a particulate pack therein (e.g., a proppant pack or a gravel pack). In other instances, viscosified treatment fluids may act to transfer hydraulic pressure in a fracturing operation or to prevent undesired leak-off of fluids into the subterranean formation in a variety of subterranean operations. In many instances, during or after the operation the viscosified treatment fluid is broken (i.e., treated to reduce the viscosity of the treatment fluid) so that the fluid may be more effectively and efficiently removed from the wellbore or formation.
However, the use of polymers in treatment fluids has several drawbacks. For example, polymers, especially high molecular weight polymers, may have a tendency to remain in the formation and plug pores, thereby reducing the productivity of the well. To address this, breakers are used to decrease the viscosity of the fluid (e.g., via polymer or crosslinker degradation), so that flowback operations can be conducted to recover the polymer or degradation products thereof. In many instances, the breakers are introduced in separate treatments, which increase the complexity, cost, and time associated with subterranean operations. In some instances, the breakers may be included in the initial treatment fluid with the polymer. Such breakers are generally engineered to delay breaking (e.g., via encapsulation or chemical modification), which increases the cost of developing and producing the delayed breaker.
Further, some polymer systems used for viscosification do not break cleanly and leave behind insoluble residues of polymers or unbroken gel clumps, which impair the conductivity of the formation. For example, guar gum (a widely used viscosifying agent) is known for its considerable amount of insoluble solids remaining on a proppant pack even after the breaker treatment.
Accordingly, a need exists for polymers that are effective with fluids having increased salinity and that are capable of being degraded, preferably without the need for a subsequent operation.